i have a 96 civic ex with a stock y8 and it bogs real bad at low rpms, no codes. ive searched and seen that it could be the o2 sensor. if it ws my o sensor wouldnt it throw a code?

 

Yes, but I would recommend getting it scanned unless you like guessing with expensive parts.

BTW The stock cast iron manifold on my car cracked and it check engine light gave a o2 sensor code it seem like it is a common problem. I also never heard an exhaust leak.

 

Generally, it should be throwing a code 1 or 41...but it is possible for there to be no code and the car can still run shitty. If its never been replaced, its definitely not a bad idea either way.

 

O2 sensor would throw code, but I doubt that's it.

 

Yes it will throw a code. I agree with packthis, if you want to throw your money away go ahead. I would get it looked at, scanning it won't do anything unless they use a scope to check the sine wave that the 02 sensor can produce then you will see if it needs to be replaced.